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Aims: Little is known about dynamic changes of the left atrial (LA) substrate over time in patients with atrial fibrillation (AF). This study aims to evaluate substrate changes following pulmonary vein isolation (PVI)., Methods and Results: In our prospective observational study, consecutive patients undergoing first PVI-only and redo ablation were included. High-density maps of the two procedures were compared. Progression or regression was diagnosed if a significant concordant decrease or increase in bipolar voltages in ≥2 segments was observed, respectively. In 28 patients (61.2 ± 9.5 years, 39% female, 53.5% persistent AF), 111.013 voltage points from 56 high-density LA maps (1.982 points/patient) were analysed. Comparing the high-density maps of the first and second procedures, in the progression group (17 patients, 61%), there was a decrease in global (-35%, P < 0.001) and all regional voltages. In the regression group (11 patients, 39%), there was an increase in global (+43%, P < 0.001) and regional voltages. Comparing the progression with the regression group, the area of low-voltage zone (LVZ) increased (+3.5 vs. -4.5 cm2, P < 0.001) and LA activation time prolonged (+8.0 vs. -9.1 ms, P = 0.005). Baseline clinical parameters did not predict progression or regression. In patients with substrate progression, pulmonary veins (PVs) were more frequently isolated (P = 0.02) and the AF pattern at recurrence was more frequently persistent (P = 0.005)., Conclusion: Our study describes bidirectional dynamic properties of the LA substrate with concordant either progressive or regressive changes. Regression occurs with reduced AF burden after the first procedure, while progression is associated with persistent AF recurrence despite durable PV isolation. The dynamic nature of LA substrate poses questions about LVZ-based ablation strategies., Competing Interests: Conflict of interest: None declared., (© The Author(s) 2023. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Aims: This study aims to investigate the clinical and biochemical characteristics of patients with atrial fibrillation (AF) referred for ablation who develop arrhythmia-induced cardiomyopathy (AiCM) as well as their long-term outcomes after catheter ablation (CA)., Methods and Results: A prospective multicentre study was conducted on consecutive AF patients who underwent CA. AiCM was defined as the development of heart failure in the presence of AF and an improvement of left ventricular fraction by at least 10% at 6 months after ablation. A subgroup of patients underwent peripheral and left atrial blood samples [galectin-3, fatty acid-binding protein 4 (FABP4), and soluble receptor for advanced glycation end products (sRAGE)] at the time of the procedure. Of the 769 patients who underwent AF ablation, 135 (17.56%) met the criteria for AiCM. Independent predictors of AiCM included persistent AF, male gender, left atrial volume, QRS width, active smoking, and chronic kidney disease (CKD). Biomarker analysis revealed that sRAGE, FABP4, and galectin-3 levels were not predictive of AiCM development nor did they differ between groups or predict recurrence. There were no differences in AF recurrence between patients with and without AiCM (30.83% vs. 27.77%; P = 0.392) during a median follow-up of 23.83 months (inter-quartile range 9-36)., Conclusions: In the subset of patients referred for AF ablation, the development of AiCM was associated with persistent AF and CKD. Biomarker analysis was not different between groups nor predicted recurrence. Patients with AiCM benefited from ablation, with a significant improvement in left ventricular ejection fraction and similar AF recurrence rates to those without AiCM., (© 2023 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Introduction: The right ventricle can be susceptible to pathologic alterations with exercise. This can cause changes to the ECG. Our aim was to identify the electrocardiographic phenotype of exercise induced (ExI) arrhythmogenic cardiomyopathy (ACM)., Methods: A retrospective analysis of ECGs at rest, peak exercise and 1 min of recovery in four groups of individuals was performed: Arrhythmogenic Cardiomyopathy with genetic confirmation (Gen-ACM; n = 16), (genetically negative) ExI-ACM ( n = 15), control endurance athletes (End; n = 16) and sedentary individuals (Sed; n = 16). The occurrence of ventricular arrhythmias (VA) and, at each stage, QRS duration, Terminal Activation Delay (TAD), the ratio of the sum of the QRS durations in the right precordials (V1-V3) over that in the left precordials (V4-V6; R/L duration ratio), the presence of complete RBBB and T-wave inversion (TWI) beyond lead V2 were evaluated., Results: At rest, complete RBBB was exclusively found in Gen-ACM (6%) and ExI-ACM (13%). No epsilon waves were identified. TWI beyond V2 was uniquely present in Gen-ACM (73%) and ExI-ACM (38%; p < 0.001). VA was present in Gen-ACM (88%); ExI-ACM (80%), End (25%) and Sed (19%; p < 0.001). The presence of R/L duration ratio of >1.2 and TAD ≥ 55 ms were not significantly different over the four groups ( p = 0.584 and p = 0.218, respectively). At peak exercise the most striking finding was a significant decrease of the R/L duration ratio in individuals with ACM, which was the result of lateral precordial QRS prolongation., Conclusion: ExI-ACM shares important ECG-features with Gen-ACM, suggesting a similar underlying pathogenesis regardless of the presence or absence of desmosomal mutations., Competing Interests: HH received personal fees from Biotronik, Pfizer-BMS, and Daiichi-Sankyo. He received unconditional research grants through the University of Antwerp and/or the University of Hasselt from Bayer, Boehringer-Ingelheim, Bracco Imaging Europe, Abbott, Medtronic, Biotronik, Daicchi-Sankyo, Pfizer-BMS, and Boston-Scientific, all outside the scope of this work. HM received personal fees from Pfizer-BMS and Abbott, both outside the scope of this work. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Miljoen, Spera, Van Kolen, Saenen, Claessen, Huybrechts, Sarkozy and Heidbuchel.)

Introduction: Unrecognized incomplete pulmonary vein (PV) isolation during the index procedure, can be a major cause of clinical recurrences of atrial fibrillation (AF) after cryoballoon (CB) ablation. We aimed to characterize the extension of the lesions produced by CB ablation and to assess the value of using an ultra-high resolution electroanatomic mapping (UHDM) system to detect incomplete CB lesions., Materials and Methods: Twenty-nine consecutive patients from the CHARISMA registry undergoing AF ablation at four Italian centers were prospectively evaluated. The Rhythmia™ mapping system and the Orion™ (Boston Scientific) mapping catheter were used to systematically map the left atrium and PVs before and after cryoablation., Results: A total of 116 PVs were targeted and isolated. Quantitative assessment of the lesions revealed a significant reduction of the antral surface area of the PV, resulting in an ablated area of 5.7 ± 0.7 cm 2 and 5.1 ± 0.8 cm 2 for the left PV pair and right PV pair, respectively ( p = 0.0068). The mean posterior wall (PW) area was 22.9 ± 2 cm 2 and, following PV isolation, 44.8 ± 6% of the PW area was ablated. After CB ablation, complete isolation of each PV was documented by the POLARMap™ catheter in all patients. By contrast, confirmatory UHDM and the Lumipoint™ tool unveiled PV signals in 1 out of 114 of the PVs (0.9%). Over 30-day follow-up, no major procedure-related adverse events were reported. After a mean follow-up of 333 days, 89.7% of patients were free from arrhythmia recurrence., Conclusion: The lesion extension achieved by the new CB ablation system involved the PV antrum, with less than 50% of the PW remaining untouched. The new system, with short tip and circular mapping catheter, failed to achieve PV isolation in only 0.9% of all PVs treated., Clinical Trial Registration: [http://clinicaltrials.gov/], identifier [NCT03793998]., Competing Interests: Authors MM and FPi were salaried Boston Scientific employees. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Spera, Narducci, Bencardino, Perna, Bisignani, Pinnacchio, Tondo, Maggio, Stabile, Iacopino, Tundo, Ferraro, De Simone, Malacrida, Pintus, Crea and Pelargonio.)

Introduction: Stereotactic arrhythmia radioablation (STAR) is a novel technique for the ablation of ventricular tachycardia in patients with contraindications to standard procedures, i.e., radiofrequency ablation., Case Presentation: We report the case of a 73-year-old man with non-ischemic dilated cardiomyopathy and recurrent VT episodes. Electroanatomic mapping showed VT prevalently of epicardial origin, but direct epicardial access through subxyphoid puncture could not be performed due to pleuropericardial adhesions from a past history of chemical pleurodesis. STAR was performed, with no VT recurrence at 6 months follow-up., Conclusions: Previous experiences with STAR have demonstrated its importance in the management of patients with refractory VT in whom other ablation strategies were not successful. Our case report highlights the use of STAR as a second choice in a patient with an unfavorable VT anatomical location and technical limitations to an optimal radiofrequency ablation. Moreover, it confirms STAR's effectiveness in the ablation of complex transmural lesions, which are more often associated with non-ischemic structural heart disease., (Copyright © 2022 Pavone, Scacciavillani, Narducci, Cellini, Pelargonio, Bencardino, Perna, Spera, Pinnacchio, Sanna, Valentini and Crea.)

Background: in patients with heart failure (HF) and atrial fibrillation (AF), AF ablation improves left ventricular ejection fraction (LVEF), along with prognosis, in a variable percentage of patients. We aimed to investigate the predictors of LVEF recovery after AF ablation and to develop a prediction model for individualized assessment., Methods: we conducted an observational, retrospective, single-centre study on 111 consecutive patients with AF and HF with impaired LVEF (<50%) undergoing ablation. Patients were divided into Responder vs. Non-Responder according to the "Universal definition of HF". Clinical predictors were evaluated by multivariate logistic regression analysis and cross-validation technique. Independent predictors were used to build an internally validated prediction model., Results: Responders (54%) had significantly shorter QRS duration and less dilated left atrium. Persistent AF and absence of a known etiology were more frequent among Responders. AF recurrence was similar between the two groups (p = 0.2), but the percentage of patient with persistent AF after ablation was significantly lower among Responders (p < 0.001). Absence of known etiology, presence of persistent AF, left atrial volume index<50 mL/m 2 , and QRS < 120 msec were independent predictors of LVEF recovery and composed the Score (AUC 0.93;95%CI 0.88-0.98-p < 0.001). Patients with Score ≤ 1 had 90% likelihood of LVEF recovery, compared to 5% in patients with 3-6., Conclusions: Patients with wide QRS, known HF etiology, dilated left atrium, and paroxysmal AF were less likely to recover LVEF after AF ablation. A new score system based on the above-mentioned parameters adequately predicts LVEF recovery after AF ablation. These results warrant confirmation and prospective validation., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Background: Literature reports 5% of recurrence/failure in paediatric accessory pathway ablations. Our aim was to investigate the reasons underlying this finding and share techniques to obtain long-term success., Methods: Thirty-nine paediatric patients referred for a repeat procedure were analysed: characteristics of the pathways and the initial and redo procedures were identified., Results: Mean age was 11.9 ± 3.3 years (59% males). Three patients (8%) had multiple accessory pathways. The most frequent location was left lateral (26%). Left sided pathway recurrence was caused mainly by poor contact (60%) and inadequate mapping (40%). For right lateral accessory pathways, poor contact accounted for 70% of failures. For antero-septal and para-Hisian locations, the use of cryoablation and choice of low radiofrequency energy delivery accounted for > 75% of failures. Long-term success strategies included choice of contact force catheters and radiofrequency applications at the ventricular insertion of the pathway and in the aortic coronary cusps. In postero-septal substrates, the main reason accounting for failure was deep or epicardial location of the pathway (37%), solved by using an irrigated tip catheter or applying lesions within the coronary sinus, or applications from both right and left postero-septal areas., Conclusion: Acute failure and post-procedure recurrence in paediatric accessory pathway ablations have multiple reasons related to the characteristics of the pathway and the technology available. Accurate understanding of the anatomy, careful mapping and pacing manoeuvers, and incorporation of new technologies contribute to achieve a definitive success in > 98% of procedures., (© 2021. The Author(s).)

Introduction: Different methods are used for atrial fibrillation (AF) cycle length (CL) measurement with variable results. Previous studies of pulmonary vein (PV) CL measurement showed contradictory results on predicting PV isolation (PVI) efficacy. A novel simple method of measuring the average of 10 consecutive Fastest Atrial Repetitive Similar morphology signal (FARS 10 )-CL to characterize local atrial activity rate was evaluated prospectively., Methods: The intra-observer reproducibility of FARS 10 -CL and traditional AF-CL measurement of continuously fragmented coronary sinus (CS) signals were tested. We prospectively enrolled 100 consecutive patients (62 ± 10 years, 72% male) undergoing wide antral PVI only ablation for persistent AF, measured PV-FARS 10 -CLs, and evaluated long-term outcome., Results: The Kendall area correlation between repeated traditional AF-CL measurements was -0.006 and between repeated FARS 10 -CL measurements in the right and left atrial appendages, CS and PVs were 0.944, 0.859, 0.882, 0.675-0.955, respectively. Patients with recurrent atrial tachyarrhythmia had significantly longer fastest PV-FARS 10 -CL (172 ± 41 vs. 156 ± 41 ms, p = .047). Patients with high burden of spontaneous low-voltage zone (LVZ) had significantly longer fastest PV-FARS 10 -CL. Freedom from recurrent tachyarrhythmia at 24 months was 85% versus 59% in patients with fastest PV-FARS 10 -CL ≤ 140 versus >140 ms, p = .0018, respectively. In multivariable analysis fastest PV-FARS 10 -CL ≤ 140 ms was the only significant predictor of freedom from recurrent tachyarrhythmia., Conclusions: FARS 10 -CL measurements have a high reproducibility in contrast to traditional AF-CL measurement of continuously fragmented CS signals. Patients with high burden of LVZ have longer fastest PV-FARS 10 -CLs. Fastest PV-FARS 10 -CL ≤ 140 ms is associated with a high success of wide antral PVI-only ablation approach in persistent AF., (© 2022 Wiley Periodicals LLC.)

Etiologic factors and long-term outcomes of catheter ablation of atrial fibrillation (AF) in young patients have not been well characterized. This study aimed to analyze the etiologic factors and outcomes of pulmonary vein isolation (PVI) in patients with young-onset AF (young-AF, defined as having first documented episode <45 years). Consecutive patients with young-AF undergoing PVI (n = 197) in 2 academic centers were enrolled and followed for 36.1 ± 24.5 months. A control group of patients with AF onset ≥45 years (n = 554) was included. The most frequent risk factors in young-AF were intensive exercise (25%), moderate-to-heavy alcohol consumption (23%), and familial AF (22%). Compared with patients with AF onset ≥45-year, patients with young-AF were more often men (82% vs 66%, p <0.001), had more frequently paroxysmal AF (81% vs 60%, p <0.001), had less left atrial dilatation (40.9 ± 6.2 mm vs 44.2 ± 7.2 mm, p <0.001), and had lower 4-year recurrence rate after last PVI procedure (22% vs 45%, p <0.001). In young-AF, structural heart disease (SHD) was the only independent predictor of recurrence. Patients with young-AF selected to undergo cryoballoon (CB) ablation were younger (35.0 ± 7.7 vs 36.6 ± 6.7 years, p = 0.035) and had less persistent AF (6% vs 24%, p = 0.004) and coronary artery disease (2% vs 7%, p = 0.02) compared with radiofrequency ablation. After excluding patients with persistent AF and SHD, there was no difference in single procedural success between radiofrequency or CB PVI (27% vs 17%, p = 0.11). In conclusion, patients with young-AF have diverse etiologies and high single and multiprocedural PVI successes. SHD is the only independent predictor of recurrence. In patients with young-AF, there is a selection bias for CB ablation., Competing Interests: Disclosures The authors have no conflicts of interest to declare., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: The Subcutaneous-ICD (S-ICD) is emerging as a suitable option for most ICD candidates, however some open issues regarding the sensing algorithm still remain., Objectives: We aimed to examine the performance of the S-ICD sensing algorithm in patients hospitalized for ST elevation myocardial infarction (STEMI), non ST elevation acute coronary syndrome (NSTE-ACS) or chronic coronary syndrome (CCS), before and after revascularization., Methods: We performed a S-ICD automated screening on 75 patients, 21 hospitalized for STEMI, 23 for NSTE-ACS and 31 for CCS, before and after percutaneous revascularization, regardless their eligibility to ICD implantation., Results: Patients did not differ in clinical, electrocardiographic and echocardiographic parameters. Rates of screening pass were significantly lower in STEMI patients compared to NSTE-ACS and CCS (5% vs 56.7% vs 81% respectively, p < .0001). The viability of the primary vector was lower in STEMI patients compared to NSTE-ACS and CCS (33% vs 56% vs 71%, p .027 respectively). After revascularization, there were no more significant differences between groups. Pairing subjects at baseline and after revascularization, STEMI subjects percentages of screening success were respectively 5% and 81% (p < .001) and the rates of primary vector viability were 33% and 81% (p .002). STEMI was the only independent predictor of screening failure at multivariate logistic regression analysis (odds ratio 10.68 confidence interval 2.77-41.38, p = .001)., Conclusion: The performance of the S-ICD and possible malfunction detections in the context of an acute ischemic event deserve further evaluation. Adequate patient selection and the development of dynamic device programming are warranted., Competing Interests: The authors report no relationships that could be construed as a conflict of interest., (© 2021 The Authors.)

Objective: About one-third of patients undergoing percutaneous coronary interventions (PCIs) for flow-limiting coronary stenosis continue to develop signs of myocardial ischemia (MI) during exercise stress test [EST], despite successful coronary revascularization. Coronary microvascular dysfunction is a likely major cause of the persistence of EST-induced MI in these patients., Patients and Methods: We studied 15 patients (14 men, age 67±5 years) fulfilling the following strict inclusion criteria: (1) recent PCI (<6 months), with drug-eluting stent, of coronary artery stenoses for stable angina, with evidence of full success (no residual stenosis >20% in any vessel); (2) persistence of ST-segment depression induction during EST. After a basal investigation, patients received either ranolazine (375 mg bid) or isosorbide-5-mononitrate (ISMN, 20 mg bid) for 3 weeks in a single-blind, randomized crossover study. Clinical assessment, symptom-limited EST, echocardiographic color-Doppler, with tissue-Doppler examination, and coronary microvascular dilator response to adenosine (CFR-ADO) and cold pressor test (CFR-CPT), assessed by transthoracic echo-Doppler, were obtained at baseline and the end of the 3-week therapy with each drug., Results: Compared to both baseline and ISMN, ranolazine showed a longer time to 1 mm ST-segment depression (404±116 s vs. 317±98 and 322±70 s, respectively; p<0.01). No differences were observed in coronary microvascular function and diastolic left ventricular function between the 2 drugs and compared to baseline., Conclusions: Our data show that ranolazine, but not ISMN, improved time to ischemia during EST. This effect, however, was independent of any effects on coronary microvascular and diastolic function.

"Early repolarization" (ER) is a frequent finding at standard electrocardiogram (ECG). In this study we assessed whether ER is associated with an increased risk of events, as recently suggested by some studies. We prospectively enrolled 4,176 consecutive subjects without any heart disease who underwent routine ECG recording. ER was diagnosed in case of typical concave ST-segment elevation ≥0.1 mV; a J wave was diagnosed when the QRS showed a notch or a slur in its terminal part. In this study we compared the 6-year outcome of all 687 subjects with ER/J wave and 687 matched subjects without ER/J wave (controls). Both groups included 335 males and 352 females, and age was 48.8 ± 18 years. Overall, 145 deaths occurred (11%), only 11 of which attributed to cardiac causes. No sudden death was reported. Cardiac deaths occurred in 5 (0.8%) and 6 (0.9%) ER/J wave subjects and controls, respectively (odds ratio [OR] 0.85, 95% confidence interval [CI] 0.26 to 2.80, p = 0.79). Both ER (OR 1.68, 95% CI 0.21 to 13.3, p = 0.62) and J wave (OR 0.91, 95% CI 0.28 to 3.00, p = 0.88) showed no association with cardiac death. Total mortality was 11.5% in the ER/J wave group and 10.6% in the control group (OR 1.10, 95% CI 0.78 to 1.56, p = 0.58). Both ER (OR 0.44, 95% CI 0.16 to 1.24, p = 0.12) and J wave (OR 1.20, 95% CI 0.85 to 1.70, p = 0.30) showed also no association with all-cause death. In subjects without any evidence of heart disease, we found no significant association of ER/J wave with the risk of cardiac, as well as all-cause, death at medium-term follow-up., (Copyright © 2017 Elsevier Inc. All rights reserved.)

While often considered to be chemically inert, the reactivity of noble gas elements at elevated pressures is an important aspect of fundamental chemistry. The discovery of Xe oxidation transformed the doctrinal boundary of chemistry by showing that a complete electron shell is not inert to reaction. However, the reductive propensity, i.e., gaining electrons and forming anions, has not been proposed or examined for noble gas elements. In this work, we demonstrate, using first-principles electronic structure calculations coupled to an efficient structure prediction method, that Xe, Kr, and Ar can form thermodynamically stable compounds with Mg at high pressure (≥125, ≥250, and ≥250 GPa, respectively). The resulting compounds are metallic and the noble gas atoms are negatively charged, suggesting that chemical species with a completely filled shell can gain electrons, filling their outermost shell(s). Moreover, this work indicates that Mg2NG (NG = Xe, Kr, Ar) are high-pressure electrides with some of the electrons localized at interstitial sites enclosed by the surrounding atoms. Previous predictions showed that such electrides only form in Mg and its compounds at very high pressures (>500 GPa). These calculations also demonstrate strong chemical interactions between the Xe 5d orbitals and the quantized interstitial quasiatom (ISQ) orbitals, including the strong chemical bonding and electron transfer, revealing the chemical nature of the ISQ.

Helium isotope variations in igneous rocks are important for relating isotopic heterogeneity to convective mixing in the Earth's mantle. High 3He/4He ratios at many ocean islands, along with lower and relatively uniform values in mid-ocean-ridge basalts (MORBs), are thought to result from a well mixed upper-mantle source for MORB and a distinct deeper-mantle source for ocean island basalts. At finer scales, 3He/4He variations along mid-ocean ridges have been related to underlying mantle heterogeneity, but relationships between the scales of geochemical segmentation and mantle convection remain enigmatic. Here we present helium isotope data for MORB glasses recovered along approximately 5,800 km of the southeast Indian ridge, and develop an approach to quantitatively relate spatial variations in geochemical and geophysical parameters at the Earth's surface. A point-to-point correlation analysis reveals structure in the helium isotope data at length scales of approximately 150 and approximately 400 km that appears to be related to secondary convection in the underlying mantle.

A key hypothesis in the generalized theory of nonequilibrium thermodynamics is the principle of microscopic time invariance as enunciated by Onsager in the 1930s. At the macroscopic level, Onsager's hypothesis is represented by a set of relations known as the Onsager reciprocal relations, which, when applied to isothermal, multicomponent diffusion, demand the symmetry of the phenomenological matrix that connects mass fluxes to chemical potential gradients. On the basis of experimentally determined diffusion coefficients and thermochemical data for the molten system CaO-Al(2)O(3)-SiO(2), the Onsager phenomenological coefficients have been computed, including an analysis of error. Within experimental uncertainty, the Onsager matrix is indeed symmetric.

A case of asymptomatic toxocariasis in a Brazilian adopted child with hypereosinophilia is described. The diagnosis is confirmed by measuring specific IgG antibodies anti-Toxocara and, in the light of growing adoptions of children coming from low standard of living extra-European countries, the authors note the importance of investigating also on those parasitosis until today rather infrequent in our country.

A conservation-of-energy equation has been derived for the spatially averaged magma temperature in a spherical pluton undergoing simultaneous crystallization and both internal (magma) and external (hydrothermal fluid) thermal convection. The model accounts for the dependence of magma viscosity on crystallinity, temperature, and bulk composition; it includes latent heat effects and the effects of different initial water concentrations in the melt and quantitatively considers the role that large volumes of circulatory hydrothermal fluids play in dissipating heat. The nonlinear ordinary differential equation describing these processes has been solved for a variety of magma compositions, initial termperatures, initial crystallinities, volume ratios of hydrothermal fluid to magma, and pluton sizes. These calculations are graphically summarized in plots of the average magma temperature versus time after emplacement. Solidification times, defined as the time necessary for magma to cool from the initial emplacement temperature to the solidus temperature vary as R(1,3), where R is the pluton radius. The solidification time of a pluton with a radius of 1 kilometer is 5 x 10(4) years; for an otherwise identical pluton with a radius of 10 kilometers, the solidification time is approximately 10(6) years. The water content has a marked effect on the solidification time. A granodiorite pluton with a radius of 5 kilometers and either 0.5 or 4 percent (by weight) water cools in 3.3 x 10(5) or 5 x 10(4) years, respectively. Convection solidification times are usually but not always less than conduction cooling times.